The menus are created from the foo.desktop file for each application.
To find them, you can do a couple of things.
First, using Synaptic package manager, select the package, then click on the “Properites” icon in the toolbar. Use the tab “Installed Files”.
Second, you can use this command line, where the “package-name” needs to be the name of your package. Tab completion works for Bash shell on the name of the package, if you know how it starts.
dpkg -L package-name | grep desktop
I found this out because I needed to change the “EXEC” string in “d2x-rebirth-demo” (the “Descent 2” rewrite) to:
/usr/local/games/d2x-rebirth/d2x-rebirth -hogdir /usr/local/games/d2x-rebirth/data